Blood Concentration-time Curve Research Articles

A validated liquid chromatography-tandem mass spectrometry method for the determination of methyl gallate and pentagalloyl glucopyranose: application to pharmacokinetic studies.

Methyl gallate (MG) and pentagalloyl glucopyranose (PGG) are bioactive phenolic compounds that are widely distributed in herbs and plant foods. Their potential activities include anti-oxidant, anti-inflammatory, anti-cancer, anti-bacterial and anti-viral activities. However, knowledge concerning the pharmacokinetic characteristics of MG and PGG is limited. The purpose of this study was to develop a sensitive and reproducible ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method to simultaneously quantify MG and PGG in rat blood samples. The linear response ranges for MG and PGG were 0.0195-20 and 0.0390-20 μM, respectively. The lower limit of quantification was 0.0195 μM for MG and 0.0390 μM for PGG. The intra- and inter-day variances were less than 15%, and accuracy was within 80-120%. This assay was successfully applied to pharmacokinetic studies in Sprague-Dawley rats after intraperitoneal administration of MG and PGG (20 mg/kg). The values of areas under the blood concentration time curves (AUC₀₋₂₄ h) for MG and PGG were 109.9 ± 73.40 and 38.78 ± 24.53 h*μM, respectively. The maximum blood concentrations (Cmax) of MG and PGG were 34.72 ± 17.32 and 6.39 ± 4.25 μM, respectively. The time required to reach the maximum concentration (Tmax) was 0.85 ± 0.70 h for both MG and PGG. The values of the elimination rate constant (Ke), elimination half-life (t1/2), volume of distribution (Vd), clearance (Cl) and mean resident time (MRTlast) were 0.056 ± 0.032 h(-1), 17.50 ± 12.25 h, 530.95 ± 247.54 L/kg, 159.91±76.05L/h/kg, 8.71 ± 2.53 h for MG and 0.023 ± 0.012 h(-1), 38.66 ± 22.89 h, 7838.89 ± 3474.72 L/kg, 30.98 ± 21.73 L/h/kg, 12.47 ± 2.77 h for PGG, respectively. In conclusion, a UPLC-MS/MS method was fully validated over a wide linear range and used to quantify the levels of MG and PGG in pharmacokinetic studies of MG and PGG in rats. The main advantages of this method are the use of small blood volumes (10 μL), rapid analysis (5 min) and excellent recoveries.

Effects of menthol on the pharmacokinetics of triazolam and phenytoin.

We have previously shown that menthol attenuates the anticoagulant effect of warfarin by increasing the expression levels of CYP3A and CYP2C in the liver. This study evaluated the effects of menthol on the pharmacokinetics of the CYP3A substrate triazolam and the CYP2C substrate phenytoin. Menthol was orally administered to mice for 7 d. Twenty-four hours after the administration of menthol, triazolam was orally administered, and the plasma concentration was measured. In addition, the CYP3A metabolic activity for triazolam and the CYP3A expression level in the liver were determined. The effects of menthol on the pharmacokinetics of phenytoin were assessed in the same manner. In the menthol-treated group, the area under the blood concentration-time curve (AUC) of triazolam was lower and its clearance was higher compared with the control group. The CYP3A metabolic activity and CYP3A expression level in the liver were significantly increased in the menthol-treated group compared with the control group. Similarly, the AUC of phenytoin was lower and the hepatic CYP2C expression level was higher in the menthol-treated group. Thus, menthol lowered the plasma concentrations of triazolam and phenytoin when concurrently administered. These effects may be attributed to an increased metabolic activity for these drugs due to the increased expression of CYP3A and CYP2C in the liver.

Influenza viral load and peramivir kinetics after single administration and proposal of regimens for peramivir administration against resistant variants.

We estimated the efficacy of the current single administration of peramivir on the basis of peramivir pharmacokinetics in the upper respiratory tract (URT) and determined the predictive peramivir concentration-time curve to assess its efficacy against viruses with decreased susceptibility to neuraminidase inhibitors. Serum, nasal swab, or aspiration samples were collected from 28 patients treated with 10 mg/kg body weight peramivir. The sequential influenza viral RNA load and susceptibility after peramivir administration were measured using a quantitative real-time reverse transcription-PCR and neuraminidase inhibition assay. The peramivir concentrations in the serum and URT after a single administration at 10 mg/kg were measured, and the predictive blood and URT peramivir concentration-time curves were determined to assess various administration regimens against resistant variants. The peramivir concentration decreased to <0.1% of the maximum concentration of drug in serum (Cmax) at 24 h after administration. Rapid elimination of peramivir from the URT by 48 h after administration may contribute to an increase in the influenza A viral load after day 3 but not to a decrease in the influenza B viral load, despite the absence of a decrease in the susceptibility to peramivir. A longer maintenance of a high level of peramivir in the URT is expected by divided administration rather than once-daily administration. When no clinical improvement is observed in patients with normal susceptibility influenza A and B, peramivir readministration should be considered. In severe cases caused by resistant variants, better inhibitory effectiveness and less frequent adverse events are expected by divided administration rather than once-daily administration with an increased dosage.

Three year outcome of childhood idiopathic nephrotic syndrome under a unified immunosuppressive protocol.

This retrospective study was performed to assess the 3 year outcome of a unified protocol for childhood idiopathic nephrotic syndrome. Cyclosporine A (CsA) or CsA plus mycophenolate mofetil (MMF) were used in patients without remission on high-dose steroid therapy. CsA was maintained at an area under the whole blood concentration-time curve up to 4 h after dose (AUC0-4 ) of 1500 and 2000 ng·h/mL in steroid-dependent nephrotic syndrome (SDNS) and steroid-resistant nephrotic syndrome (SRNS), respectively. Ninety-one children were enrolled in the study (SDNS, n = 64; SRNS, n = 18). Patients were divided into minimal change (MC) and focal segmental glomerulosclerosis (FSGS) groups. Three year outcome was evaluated using clinical severity defined as degree of dependence on immunosuppressive therapy for maintenance of remission. In the SDNS group, the numbers of MC and no biopsy were 51 and 13, respectively. No patient had FSGS. Twelve SRNS patients had FSGS and six had MC. In SDNS, 15/64 patients (23%) received no medication. CsA was effective as steroid-sparing agent in 31/38 patients (82%). MMF was effective in all eight patients for whom CsA was unsuccessful. Remission rate in the SRNS group was 14/18 (78%; eight with CsA, and six with a combination of CsA + MMF). Five of the 14 SRNS remission patients received methylprednisolone pulse therapy. Four were resistant to therapy, and had impaired renal function. The clinical severity of MC and FSGS overlapped. Treatment with CsA and combination of CsA plus MMF was useful for SDNS and for remission induction in SRNS.

Likelihood approach for evaluating bioequivalence of highly variable drugs.

Bioequivalence (BE) is required for approving a generic drug. The two one-sided tests procedure (TOST, or the 90% confidence interval approach) has been used as the mainstream methodology to test average BE (ABE) on pharmacokinetic parameters such as the area under the blood concentration-time curve and the peak concentration. However, for highly variable drugs (%CV > 30%), it is difficult to demonstrate ABE in a standard cross-over study with the typical number of subjects using the TOST because of lack of power. Recently, the US Food and Drug Administration and the European Medicines Agency recommended similar but not identical reference-scaled average BE (RSABE) approaches to address this issue. Although the power is improved, the new approaches may not guarantee a high level of confidence for the true difference between two drugs at the ABE boundaries. It is also difficult for these approaches to address the issues of population BE (PBE) and individual BE (IBE). We advocate the use of a likelihood approach for representing and interpreting BE data as evidence. Using example data from a full replicate 2 × 4 cross-over study, we demonstrate how to present evidence using the profile likelihoods for the mean difference and standard deviation ratios of the two drugs for the pharmacokinetic parameters. With this approach, we present evidence for PBE and IBE as well as ABE within a unified framework. Our simulations show that the operating characteristics of the proposed likelihood approach are comparable with the RSABE approaches when the same criteria are applied.

Short-term effects of highly-bioavailable curcumin for treating knee osteoarthritis: a randomized, double-blind, placebo-controlled prospective study

Background We previously developed a surface-controlled water-dispersible form of curcumin and named it Theracurmin® (Theracurmin; Theravalues, Tokyo, Japan). The area under the blood concentration–time curve of Theracurmin in humans was 27-fold higher than that of curcumin powder. We determined the clinical effects of orally administered Theracurmin in patients with knee osteoarthritis during 8 weeks of treatment.Methods Fifty patients with knee osteoarthritis of Kellgren–Lawrence grade II or III and who were aged more than 40 years were enrolled in this randomized, double-blind, placebo-controlled, prospective clinical study. Placebo or Theracurmin containing 180 mg/day of curcumin was administered orally every day for 8 weeks. To monitor adverse events, blood biochemistry analyses were performed before and after 8 weeks of each intervention. The patients’ knee symptoms were evaluated at 0, 2, 4, 6, and 8 weeks by the Japanese Knee Osteoarthritis Measure, the knee pain visual analog scale (VAS), the knee scoring system of the Japanese Orthopedic Association, and the need for nonsteroidal anti-inflammatory drugs.Results At 8 weeks after treatment initiation, knee pain VAS scores were significantly lower in the Theracurmin group than in the placebo group, except in the patients with initial VAS scores of 0.15 or less. Theracurmin lowered the celecoxib dependence significantly more than placebo. No major side effects were observed with Theracurmin treatment.Conclusion Theracurmin shows modest potential for the treatment of human knee osteoarthritis.

P1-5-4 - Association of Abcg2 Polymorphism with Plasma Concentrations of Axitinib in Patients with Renal Cell Carcinoma

Background: Axitinib is a selective inhibitor for VEGF receptors 1, 2, and 3 on renal cell carcinoma (RCC). The plasma concentrations and area under the blood concentration-time curve (AUC) of axitinib are known to correlate with response rate and survival rate in RCC patients. Breast cancer resistance protein (BCRP, ABCG2 gene) is an efflux ABC transporter, which is expressed at the apical membrane in intestine, and is involved in the absorption and excretion of various drugs. Several studies have demonstrated that ABCG2 polymorphism affects blood concentrations of oral anticancer drugs, especially molecular targeted drugs. To explore the relationship between pharmacokinetics and pharmacogenetics, we analyzed plasma concentrations of axitinib and ABCG2 polymorphism in RCC patients.Method: Eight RCC patients treated with axitinib at Nagoya University Hospital were enrolled in this study. All patients were orally administered 5mg axitinib twice a day. The blood samples were collected before (0 hr) and 0.5, 1, 2, 4 and 6 hr after administration of axitinib (6 points) on day 1 and day 8, respectively. The plasma concentrations of axitinb were analyzed by UPLC-MS/MS. The genetic polymorphism of ABCG2 was determined by real-time PCR. This study was approved by the ethical committee of Nagoya University Hospital, and all patients gave written informed consent.Result: The standard concentration-curve of axitinib in human plasma was linear in the range of 1-100 ng/mL. Intra- and inter-day precision ranged from 1.5 to 7.9% and accuracy were all less than 15%. The maximum concentration and AUC of axitinb in one patient carrying ABCG2 421A/A genotype were markedly higher than those carrying ABCG2 421C/A or C/C genotype on day 8.Conclusion: The plasma concentration of axitinb was analyzed accurately and reproducibly by UPLC-MS/MS. Our findings suggest that ABCG2 polymorphism, especially 421A/A genotype, may influence the plasma concentration of axitinib.

Pharmacokinetic and CYP3A5 pharmacogenetic differences between once- and twice-daily tacrolimus from the first dosing day to 1 year after renal transplantation.

Aim & patients & methods: This study investigated 24-h pharmacokinetic and CYP3A5 pharmacogenetic differences between once-daily tacrolimus (Tac-q.d.) versus twice-daily tacrolimus (Tac-b.i.d.) pretransplantation and at 1 month and 1 year post-transplantaion. The dose-adjusted trough level (Cmin) and area under the blood concentration-time curve from 0 to 24 h (AUC₀₋₂₄) increased twofold within 1 year post-transplantation with both formulations and the two genotypes. Good correlations were observed between the AUC₀₋₂₄ and Cmin for both formulations. However, the dose-adjusted Cmin, but not dose-adjusted AUC₀₋₂₄, was approximately 30% lower for Tac-q.d. than for Tac-b.i.d. Although the dose-adjusted Cmin was lower for Tac-q.d. than for Tac-b.i.d. in both genotypes, the dose-adjusted AUC₀₋₂₄ was approximately 25% lower for Tac-q.d. than for Tac-b.i.d. in CYP3A5 expressers, but not in nonexpressers during the study period. These results suggested that the approximately 30% lower Cmin for Tac-q.d. than for Tac-b.i.d. may have achieved the same AUC₀₋₂₄ with both formulations and may be associated with CYP3A5 pharmacogenomic differences, especially in CYP3A5 expressers, between Tac-b.i.d. and Tac-q.d.

Assessment of intestinal availability (FG) of substrate drugs of cytochrome p450s by analyzing changes in pharmacokinetic properties caused by drug-drug interactions.

In this study, we developed the drug-drug interaction (DDI) method as a new assessment technique of intestinal availability (F(G), the fraction of drug transferred from the intestinal enterocytes into the liver, escaping from intestinal metabolism) based on the clearance theory. This method evaluates F(G) from changes caused by DDIs in the area under the blood concentration-time curve and in the elimination half-life of victim drugs. Application of the DDI method to data from the literature revealed that the mean and S.D. of F(G) values for 20 substrate drugs of CYP3A was 0.56 ± 0.29, whereas that for 8 substrate drugs of CYP2C9, CYP2C19, and CYP2D6 was 0.86 ± 0.11. These results were consistent with the fact that intestinal metabolism is mediated predominantly by CYP3A. The DDI method showed reasonable correlations with the conventional i.v./p.o. method and the grape fruit juice (GFJ) method (coefficients of determination of 0.41 and 0.81, respectively). The i.v./p.o. method was more susceptible to fluctuations in the hepatic blood flow rate compared with the DDI and GFJ methods. The DDI method evaluates F(G) separating from the absorption ratio (F(A)) although it requires approximation of F(A). Since preciseness of approximation of F(A) does not greatly affect the evaluation of F(G) by the DDI method, we proposed a reasonable approximation method of F(A) for the evaluation of F(G) in the DDI method. The DDI method would be applicable to a broad range of situations in which various DDI data are utilizable.

Differential Effects of Rifampin and Ketoconazole on the Blood and Liver Concentration of Atorvastatin in Wild-Type and Cyp3a and Oatp1a/b Knockout Mice

Atorvastatin is eliminated by CYP3A4 which follows carrier-mediated uptake into hepatocytes by OATP1B1, OATP1B3, and OATP2B1. Multiple clinical studies demonstrated that OATP inhibition by rifampin had a greater impact on atorvastatin systemic concentration than itraconazole-mediated CYP3A4 inhibition. If it is assumed that the blood and hepatocyte compartments are differentiated by the concentration gradient that is established by OATPs, and if the rate of uptake into the hepatocyte is rate-determining to the elimination of atorvastatin from the body, then it is hypothesized that blood concentrations may not necessarily reflect liver concentrations. In wild-type mice, rifampin had a greater effect on systemic exposure of atorvastatin than ketoconazole, as the blood area under the blood concentration-time curve increased 7- and 2-fold, respectively. In contrast, liver concentrations were affected more by ketoconazole than by rifampin, as liver levels increased 21- and 4-fold, respectively. Similarly, in Cyp3a knockout animals, 39-fold increases in liver concentrations were observed despite insignificant changes in the blood area under the blood concentration-time curve. Interestingly, blood and liver levels in Oatp1a/b knockout animals were similar to wild types, suggesting that Oatp1a/b knockout may be necessary but not sufficient to completely describe atorvastatin uptake in mice. Data presented in this work indicate that there is a substantial drug interaction when blocking atorvastatin metabolism, but the effects of this interaction are predominantly manifested in the liver and may not be captured when monitoring changes in the systemic circulation. Consequently, there may be a disconnect when trying to relate blood exposure to instances of hepatotoxicity because a pharmacokinetic-toxicity relationship may not be obvious from blood concentrations.

Menthol reduces the anticoagulant effect of warfarin by inducing cytochrome P450 2C expression

Recently, it was reported that the anticoagulant effect of warfarin was reduced when patients receiving warfarin also took menthol. The purpose of this study is to reveal the mechanism of this reduced anticoagulant effect of warfarin from the pharmacokinetic point of view. Warfarin was orally administered to mice 24h after the administration of menthol for 2days, and the plasma warfarin concentration was measured. In the menthol administration group, the area under the blood concentration time curve of warfarin was decreased by approximately 25%, while total clearance was increased to 1.3-fold compared to the control group. The hepatic cytochrome P450 (CYP) 2C protein expression level in the menthol administration group was significantly increased compared to that in the control group. An increase in the nuclear translocation of constitutive androstane receptor (CAR) was also observed. The addition of menthol to human hepatic cells, HepaRG cells, caused an increase in the mRNA expression level of CYP2C9. The results of this study revealed that menthol causes an increase in CYP2C expression levels in the liver, which leads to an enhancement of warfarin metabolism, resulting in a decreased anticoagulant effect of warfarin. It was also suggested that menthol acted directly on the liver and increased the expression level of CYP2C by enhancing the nuclear translocation of CAR.

Intraperitoneal Injection Improves the Uptake of Nanoparticle-Labeled High-Density Lipoprotein to Atherosclerotic Plaques Compared With Intravenous Injection

Background— The aim of this study was to assess whether high-density lipoprotein (HDL) labeled with superparamagnetic iron oxide nanoparticles (SPIOs) and quantum dots was able to detect atherosclerotic lesions in mice after intravenous and intraperitoneal injection by multimodal imaging. Methods and Results— Nanoparticle-labeled HDLs (NP-HDLs) were characterized in vitro by dynamic light scattering and size exclusion chromatography with subsequent cholesterol and fluorescence measurements. For biodistribution and blood clearance studies, NP-HDL SPIOs radiolabeled with 59 Fe (NP-HDL 59Fe-SPIOs ) were injected intravenously or intraperitoneally into ApoE knockout mice (n=6), and radioactivity was measured using a gamma counter. NP-HDL accumulation within atherosclerotic plaques in vivo and ex vivo was estimated by MRI at 7 Tesla, ex vivo confocal fluorescence microscopy, x-ray fluorescence microscopy, and histological analysis (n=3). Statistical analyses were performed using a 2-tailed Student t -test. In vitro characterization of NP-HDL confirmed properties similar to endogenous HDL. Blood concentration time curves showed a biexponential decrease for the intravenous injection, whereas a slow increase followed by a steady state was noted for intraperitoneal injection. Radioactivity measurements showed predominant accumulation in the liver and spleen after both application approaches. NP-HDL 59Fe-SPIOs uptake into atherosclerotic plaques increased significantly after intraperitoneal compared with intravenous injection ( P &lt;0.01). In vivo MRI showed an increased uptake of NP-HDL into atherosclerotic lesions after intraperitoneal injection, which was confirmed by ex vivo MRI, x-ray fluorescence microscopy, confocal fluorescence microscopy, and histological analysis. Conclusions— In vivo MRI and ex vivo multimodal imaging of atherosclerotic plaque using NP-HDL is feasible, and intraperitoneal application improves the uptake within vessel wall lesions compared with intravenous injection.

Estimation of chloroform inhalation dose by other routes based on the relationship of area under the blood concentration-time curve (AUC)-inhalation dose to chloroform distribution in the blood of rats

The present study investigated the time-course changes of concentration of chloroform (CHCl3) in the blood during and after exposure of male rats to CHCl3 by inhalation. Increasing the dose of CHCl3 in the inhalation exposed groups caused a commensurate increase in the concentration of CHCl3 in the blood and the area under the blood concentration-time curve (AUC). There was good correlation (r = 0.988) between the inhalation dose and the AUC/kg body weight. Based on the AUC/kg body weight-inhalation dose curve and the AUC/kg body weight after oral administration, inhalation equivalent doses of orally administered CHCl3 were calculated. Calculation of inhalation equivalent doses allows the body burden due to CHCl3 by inhalation exposure and oral exposure to be directly compared. This type of comparison facilitates risk assessment in humans exposed to CHCl3 by different routes. Our results indicate that when calculating inhalation equivalent doses of CHCl3, it is critical to include the AUC from the exposure period in addition to the AUC after the end of the exposure period. Thus, studies which measure the concentration of volatile organic compounds in the blood during the inhalation exposure period are crucial. The data reported here makes an important contribution to the physiologically based pharmacokinetic (PBPK) database of CHCl3 in rodents.

Effects of gender on pharmacokinetics of propofol

Objective To evaluate the effects of gender on the pharmacokinetics of propofol in patients.Methods Twenty ASA physical status Ⅰ or Ⅱ patients of both sexes (10 male,10 female),aged 42-59 yr,weighing 46-76 kg,scheduled for elective surgery for gastrointestinal cancer,were randomly divided into 2 gender groups (n =10 each):male group and female group.Combined intravenous-inhalational anesthesia was performed during surgery.Anesthesia was induced with iv injection of 2％ propofol 2 mg/kg,remifentanil 1.5 μg/kg,and suxamethonium chloride 1.5 mg/kg.The patients were tracheally intubated and mechanically ventilated.Anesthesia was maintained with inhalation of the mixture of 1％-2 ％ isoflurane and nitrous oxide (N2 O ∶ O2 =1 ∶ 1.),iv infusion of remifentanil 0.2-0.3 μg/kg and intermittent iv boluses of atracurium.Blood samples were taken from the central vein before propofol administration,and at 1,2,3,4,6,10,15,30,45,60,90,120,180,240,360 and 720 min after propofol administration for determination of the plasma concentration of propofol by high-performance liquid chromatography.The blood concentration-time curve of propofol was drawn and the pharmacokinetic parameters were calculated.Results The blood concentrations of propofol were significantly lower at each time points within 10 rmin after administration of the single bolus of propofol in female group than in male group (P ＜0.05).The blood concentration-time curves of propofol were fitted to a three-compartment open model in the 2 groups.The central volume of distribution and clearance rate were significantly larger in female patients than in male patients (P ＜ 0.05).Conclusion After iv injection of propofol,the blood concentration of propofol is lower,and the central volume of distribution and clearance rate are larger in female than in male,suggesting that gender has significant effect on pharmacokinetics of propofol. Key words: Sex factor; Propofol; Pharmacokinetics

Pharmacokinetics of a self-microemulsifying drug delivery system of tacrolimus

This study evaluated the pharmacokinetics of tacrolimus (Tac) in a novel self-microemulsifying drug delivery system (SMEDDS) for improved oral administration. SMEDDS Tac consisted of ethyl oleate as the oily phase, Solutol HS 15 as the surfactant and glycofurol as the co-surfactant and contained 0.5mg/mL tacrolimus. Blood and tissue concentrations of tacrolimus from two study groups (oral application of SMEDDS Tac and Prograf®) were determined using ELISA technique following tacrolimus administration in rats. There was no difference between area under the whole blood concentration–time curve in the SEDDM Tac group and the Prograf® group. Maximum concentrations of the drug were three times higher (P<0.05) in the SEDDM Tac group accompanied by a 3-fold earlier peak time. Elimination half-life was significantly lower in the SEDDM Tac group. Application of SMEDDS Tac increased tissue accumulation. Already after 15min, Tac levels of small intestine, liver, kidney, spleen, heart and bone marrow were significantly higher in the SMEDDS Tac group than in the Prograf® group (P<0.05). However, the Tac concentration in the kidney was significantly lower in the SMEDDS Tac group. Formulation of SMEDDS did not affect blood-brain barrier function. The SMEDDS is a potentially useful method for a local delivery of Tac to target organs. The selection of the optimum SMEDDS Tac composition might have advantage as an alternative oral dosage form for Tac.

Ciclosporin Population Pharmacokinetics and Bayesian Estimation in Thoracic Transplant Recipients

Therapeutic drug monitoring of ciclosporin has been recognized as an essential tool in the management of allograft transplant recipients, as it could help improve their outcome. However, there is still no consensus about the optimal method for monitoring ciclosporin after thoracic transplantation. Better knowledge of the pharmacokinetics of ciclosporin in thoracic transplant patients and design of tools dedicated to ciclosporin monitoring could help its practice and its outcome in this population of patients. The aims of this study were to (i) investigate the population pharmacokinetics of ciclosporin in thoracic (heart or lung) transplant patients and study the influence of a range of potential covariates, including demographic, clinical and genetic factors, on pharmacokinetic parameters; and (ii) develop a Bayesian estimator able to predict the individual pharmacokinetic parameters and exposures indices in this population of patients. The analysis was performed with 187 full pharmacokinetic profiles obtained in 57 lung and 19 heart transplant patients within the first year post-transplantation. A population pharmacokinetic model was developed by non-linear mixed-effects modelling using NONMEM(®) (version 7.1) from an index dataset (118 profiles). On the basis of this population model and a limited number of blood samples, a Bayesian estimator able to determine ciclosporin area under the blood concentration-time curve (AUC) during a dosage interval was built and evaluated in the validation dataset (69 profiles). Ciclosporin pharmacokinetics were described using a two-compartment model with time-lagged first order absorption and first-order elimination. The final population model included sex as a covariate: ciclosporin apparent oral clearance was on average 37 % faster in male than in female patients (34.8 vs. 25.4 L/h, p < 0.001). Good predictive performance of the Bayesian estimator was obtained using three blood concentrations measured at 40 min, 2 h and 4 h post-dose, with a non-significant bias of -5 % between the estimated and the reference trapezoidal AUC and a good precision (relative mean square error = 13 %). Ciclosporin population pharmacokinetic analysis in thoracic transplant patients (including patients with cystic fibrosis) showed a significant influence of sex on apparent clearance. The Bayesian estimator developed in this study yielded accurate prediction of ciclosporin exposure in this population throughout the first year post-transplantation. This tool may allow routine ciclosporin dose individualization.

Drinkable Preparation of Theracurmin Exhibits High Absorption Efficiency—A Single-Dose, Double-Blind, 4-Way Crossover Study

Curcumin has various biological activities including antioxidant and antiinflammatory actions, and alcohol detoxification. However, because of its poor absorption efficiency, it is difficult for orally administered curcumin to reach blood levels sufficient to realize its bioactivities. We have generated capsules and tablets containing Theracurmin, a highly absorptive curcumin. In addition, we recently created a drinkable preparation of Theracurmin. To evaluate the absorption efficiency of this type of curcumin, we performed a single-dose, double-blind, 4-way crossover study. We compared plasma curcumin levels after the administration of Theracurmin beverage and 3 other drinkable types of curcumin sold in Japan. Twenty-four healthy subjects (male/female=13/11, age: 23-32) were administered with these 4 drinkable preparations of curcumin. The area under the blood concentration-time curve at 0-8 h was found to be 1.5 to 4.0-fold higher with Theracurmin than with the other 3 kinds of curcumin beverage. Moreover, maximal plasma curcumin concentrations (0-8 h) of Theracurmin were 1.8 to 3.8 times higher than those of the other 3 curcumin beverages. These data indicate that our newly prepared Theracurmin beverage exhibits a much better absorption efficiency than other kinds of curcumin beverage sold in Japan.

Dose Adjustment Strategy of Cyclosporine A in Renal Transplant Patients: Evaluation of Anthropometric Parameters for Dose Adjustment and C0 vs. C2 Monitoring in Japan, 2001-2010

The optimal use and monitoring of cyclosporine A (CyA) have remained unclear and the current strategy of CyA treatment requires frequent dose adjustment following an empirical initial dosage adjusted for total body weight (TBW). The primary aim of this study was to evaluate age and anthropometric parameters as predictors for dose adjustment of CyA; and the secondary aim was to compare the usefulness of the concentration at predose (C0) and 2-hour postdose (C2) monitoring. An open-label, non-randomized, retrospective study was performed in 81 renal transplant patients in Japan during 2001-2010. The relationships between the area under the blood concentration-time curve (AUC0-9) of CyA and its C0 or C2 level were assessed with a linear regression analysis model. In addition to age, 7 anthropometric parameters were tested as predictors for AUC0-9 of CyA: TBW, height (HT), body mass index (BMI), body surface area (BSA), ideal body weight (IBW), lean body weight (LBW), and fat free mass (FFM). Correlations between AUC0-9 of CyA and these parameters were also analyzed with a linear regression model. The rank order of the correlation coefficient was C0 > C2 (C0; r=0.6273, C2; r=0.5562). The linear regression analyses between AUC0-9 of CyA and candidate parameters indicated their potential usefulness from the following rank order: IBW > FFM > HT > BSA > LBW > TBW > BMI > Age. In conclusion, after oral administration, C2 monitoring has a large variation and could be at high risk for overdosing. Therefore, after oral dosing of CyA, it was not considered to be a useful approach for single monitoring, but should rather be used with C0 monitoring. The regression analyses between AUC0-9 of CyA and anthropometric parameters indicated that IBW was potentially the superior predictor for dose adjustment of CyA in an empiric strategy using TBW (IBW; r=0.5181, TBW; r=0.3192); however, this finding seems to lack the pharmacokinetic rationale and thus warrants further basic and clinical investigations.

Role of Insulin Resistance in the Pathogenesis and Development of Type 2 Diabetes in WBN/Kob-&lt;i&gt;Lepr&lt;sup&gt;fa&lt;/sup&gt;&lt;/i&gt; Rats

ABSTRACTWBN/Kob-Leprfa (fa/fa) rats have been identified as a new animal model of type 2 diabetes (T2DM), as they are characterized by impaired pancreatic insulin secretion and severe insulin resistance. Our previous study demonstrated impaired insulin secretion and its involvement in hyperglycemia in fa/fa rats. The present study was aimed at elucidating the role of insulin resistance in the development and progression of diabetes in these animals. Troglitazone (TGZ) was used as an insulin sensitizer. Insulin resistance and insulin secretory capacity were measured by a homeostasis model assessment of insulin resistance and the area under the blood concentration–time curve for plasma insulin levels after intravenous glucose tolerance testing, respectively. The fa/fa rats exhibited marked insulin resistance between 5 and 11 weeks of age, compared with age-matched Wistar rats. The insulin secretory capacity of fa/fa rats was higher than that of Wistar rats at 5 weeks of age, but decreased by 50% between 9 and 11 weeks of age. The fa/fa rats were fed a standard diet, with or without 0.2% w/w TGZ, for 4 weeks. Treatment with TGZ significantly improved insulin resistance, hyperglycemia and hypertriglyceridemia in both prophylactic and therapeutic study groups. These results suggest that insulin resistance is markedly involved in the development and progression of T2DM in fa/fa rats.

Modification of a Dioxygen Carrier, HemoCD, with PEGylated Dendrons for Extension of Circulation Time in the Bloodstream

A supramolecular diatomic receptor, hemoCD, was modified with PEGylated dendrons to extend its circulation time in the bloodstream. The core component was 4-oxo-4-[[4-(10,15,20-tris(4-sulfonatophenyl)-21H,23H-porphin-5-yl)phenyl]amino]butanoic acid (Por-COOH). The building block of the dendrons was Fmoc-4-amino-4-(2-carboxyethyl)heptanedioic acid (FmocTA), which was condensed with α-amino-ω-methoxy-poly(ethylene glycol) (PEG(5000)-NH(2)) to yield an FmocG1-dendron. After deprotection, the G1-dendron was condensed with Por-COOH to yield G1-Por. A precursor (FmocNA) of an FmocG2-dendron was prepared via a condensation reaction of 4-amino-4-(2-t-butoxycarbonylethyl)heptanedioic acid di-t-butyl ester (TA-E) with FmocTA followed by hydrolysis of the resultant nona-carboxylic acid nona-t-butyl ester. Condensation of FmocNA with PEG(5000)-NH(2) yielded an FmocG2-dendron. After deprotection, the G2-dendron was condensed with Por-COOH to yield G2-Por. The ferrous complexes of G1- and G2-Pors formed stable 1:1 inclusion complexes with Py3CD, a per-O-methylated β-cyclodextrin dimer with a pyridine linker, in aqueous solution yielding supramolecular complexes designated as G1-hemoCD and G2-hemoCD, respectively. Both G1- and G2-hemoCDs bound molecular oxygen, with the O(2) affinities (P(1/2)) of hemoCD, G1-, and G2-hemoCDs at pH 7.4 and 37 °C being 22, 20, and 20 Torr, respectively. The modification of hemoCD with the dendrons did not cause destabilization of the O(2) adducts via autoxidation, as indicated by their half-lives (t(1/2)) of 6.8, 6.1, and 5.5 h for hemoCD, G1-, and G2-hemoCDs, respectively. The blood concentration-time curves of G1- and G2-hemoCDs injected into the bloodstream of rats exhibited two phases, with the half-lives of the fast and slow decays being 0.45 and 5.3 h, respectively, for G1-hemoCD, and 0.20 and 12.8 h, respectively, for G2-hemoCD. The half-lives of hemoCD were 0.02 and 0.50 h, respectively. The circulation time of hemoCD was markedly extended by its modification with the PEGylated dendrons, which was very effective in protecting hemoCD against opsonization for uptake by the reticuloendothelial system.